[HWooldridge]

I bought some 4043 rod, a couple of 3/32" pure tungsten electrodes and a 1/2" gas lens then cranked the argon flow to 25 CFH. The welding got much easier but was still pockmarked by areas that simply would not weld together. I assume this trouble was because this repair was a casting and likely oil soaked. However, by stopping to sandblast periodically, I was able to finish the job. I also welded a piece of material across the ends of the broken fragments so they are all joined by a homogenous piece. After milling away the excess, the piece looked fresh from the factory. The maintenance guys at the plant were suitably impressed (especially since none of them were willing to fix it).

Thanks to all who answered, this forum is a real blessing to all of us who participate and contribute.